Engine starting mechanism



Jan. 4, 1944. R. M. NARDONE 2,338594 ENGINE STARTING MECHANISM OriginalFiled Aug. 8, 1940 2 Sheets-Sheet 1 Jan. 4, 1944. R M NARDONE 2,338,594

ENGINE STARTING MECHANISM Original Filed Aug. 8, 1940 2 Sheets-Sheet 2lllll o/ lzeo Nardo/le Psanaausn. '4, 1944 ENGINE STARTING MECHANISMRomeo M. Nardone, Westwood, N. J., assignor to Bendix AviationCorporation,

South Bend,

Ind., a corporation of Delaware Original application August 8, 1940,Serial No.

351,831. Divided and this application September 26, 1942, Serial No.459,819

1 Claim. (Cl. 172-36) This invention relates to engine startingmechanism, and more particularly lto the starting of the several enginesconstituting the complete power plant of a heavier-than-air-flyingdevice such as an airplane or dirigible.

An object of the invention is to provide for the successive cranking ofthe several engines of a multi-engine aircraft by the successiveapplication thereto of a portable prime mover adapted to transmitstarting torque thereto through connections operating to transmit suchtorque directly and through the instrumentality of an automaticallyengaged and disengaged clutch mechanism, the engagement of which isimmediate in response to the coupling of the portable prime mover intooperative position in relation thereto, and the disengagement of whichfollows immediately upon development of self-sustaining speed in theengine itself.

4Another object is to provide a portable unit for the described purposeand characterized by novel features .in the construction andinter-relationship of parts.

These and other objects of the invention will become apparent frominspection of the following specification when read with reference tothe accompanying drawings wherein is illustrated the preferredembodiment of the invention. It is to be expressly understood, however,that the drawings are for the purposeqof illustration only, and are notdesigned as a definition of the limits of the invention, reference beinghad tothe appended claim for this purpose.

In the drawings:

Flg. 1 is a view, partly in section and partly in elevation, of aldevice embodying the invention, as said device appears when in positionfor the starting of one of a series of engines to be successivelystarted; the view showing, however,

only one end of the portable prime mover constituting a component partof the device;

Fig. 2 is a view, partly in section and partly in elevation, showing thecomplete prime mover including the manual supporting means therefor andthe cable leading therefrom to the source of energy: and

Fig. 3 is apwiring diagram showing the electrical connections involvedfor energization of the prime mover shown in Fig. 2.

In the drawings the lprime mover is shown as enclosed within a portablehousing I I from which extends the armature driven shaft I2 having theconventional type of pin and cam slot attachment to the coupling memberI3 rotatably mounted in a ball-bearing receiving casing I4 which isbolted or otherwise fixedly secured, as indicated'at I8, to a portion I9of the cowling which encloses the power plant portion of the aircraft.The transmission mechanism which drivably connects the prime mover tothe engine crankshaft (or engine crankshaft connected element) 2I isshown as enclosed within a sectional housing constituted by a centralsection 23 having a flange 24 to receive bolts 29 by which the unit isanchored to a portion 21 of the crankcase or housing enclosing theengine crankshaft, the said anchoring means also serving to secure theflange 29 of the inwardly extending member 3l in which are receivedcertain parts (hereinafter described) which influence the action of theautomatically engaging clutch element 34 in which the torquetransmitting elements of the unit terminate. Ihe flexible shaft 31 whichdrivably connects the prime mover with the transmission mechanism isenclosed in a exible housing 39 which is secured at one end to theextension 39 of the coupling housing and at its opposite end to theclosure plate 4I which fastens to the section 43 of the transmissionunit housing as indicated at 44. Drivably connected to the flexibleshaft is a pinion 45 that meshes with a spur gear 41. The housingsection 43 supports therein a pair of bearings 48 that are maintained inspaced relation by means of a sleeve carried on a lay shaft 49 which isrotatably supported by said bearings and which, in the form of theinvention illustrated,'is integral with the spur gear". Also integralwith gear 41 is a pinion 5| adapted to engage an internal gear 52. Gear52 is preferably made integral with a small spur gear 53, and the twogears are rotatably mounted, as by means of a bushing, on a stub shaft54 that extends outwardly from, and is drivably connected to, a barrel58 having a closed end, the stub shaft 54 being integral with saidclosed end in the illustrated embodiment of the invention. Ball-bearings51, 58, carried by the inner housing section 23, are preferably employedfor rotatably mounting the barrel 56.

Gear 53 constitutes a sun gear for a plurality of planetary gears 59that are rotatably mounted on the barrel end, and mesh with an internalgear 6I which is` fixedly lmounted within the housing by means of screws92. Preferably three planetary gears 59 are employed, and one of theseis shown in section in Fig. 1. These gears 59 are preferably spaced 120apart, and each ofl the planetary gears is rotatably mounted by means ofa ball-bearing 63 carried by a cyhndrical part which is integral with orcountersunk at its inner end in the end wall of barrel 88. and threadedinto the barrel end, are screws which support a retaining ring 84 forthe bearings and planetary gears.

The electric motor shaft I2 is adapted to drive the engine engagingmember 34 through the train of reduction gearing described above. The'member I4 constitutes one element of a jaw clutch, the other clutchelement 35 being formed integral with or carried by the rotating part'2| of the engine to be cranked.

There is preferably employed a multiple disc clutch embodying aplurality of friction discs 1|, a number of said discs being splined tothe inner surface of lbarrel 88, and the remainder `being splined to theouter surface of an interiorly threaded nut 12. Resilient means such asa plurality of coil springs 13 and an adjusting nut 14, which isthreaded into the inner end of barrel 58, are provided for varying thepressure with which discs 1| are maintained in engagement,

Mounted for rotary and longitudinal movement within nut 12 is a threadedshaft 18 which is longitudinally splined at its inner end to drivablyengage a correspondingly splined. tubular hub portion of the jaw clutchmember 34. Movement of threaded shaft 18 to the left, as viewed in Fig.1, relative to nut 12, is positively limited by means of a member 11threaded on the outer end of shaft 18 and constituting a stop shoulderfor engagement with a shoulder formed interiorly of nut 12. Preferably acoil spring 19 is interposed between `law clutch member 34 and shaft 18,a portion of said spring extending into a recess formed in the inner endof the shaft, to yieldingly resist relative movement of the clutchmember towards the shaft.

The starter is preferably provided with oil sealing means for preventingoil in the engine crankcase 21 from seeping into the starter housing.For this purpose the inner portion of member 3| is bent inwardly towardjaw member 34, and is provided with a central opening which is slightlylarger in diameter than the outer diameter of the head of jaw member 34.Preferably member 3| is strengthened adjacent said opening by being bentor curved, and carries a washer 8| that may be formed of leather and issecured in any suitable manner to the shoulder adjacent the bend ofmember 3|. Normally the central portion of washer 8| is held inengagement with the adjacent surface of the head of jaw member 34 bymeans of a sleeve which slidably surrounds the cylindrical portion ofthe jaw clutch member and abuts at its opposite end against a flangeprovided on nut 12. The above described oil seal means is not claimedper se in this application as it constitutes the subject matter ofclaims in Patent No. 1,962,397 granted to Raymond P. Lansing on June 12,1934. Preferably-as in said Lansing patent No. 1,962,397--the outerperiphery of member 34 carries la split-ring 83 retained in position bymeans of a surrounding resilient member 84 Extending through thesecarrying parts.,

assasss As has been pointed out. it is desirable for shaft 18 and Jawclutch member 34 to have relative longitudinal movement, but theseelements must rotate in unison. For this Purpose the two parts aresplined together as previously described. It is also desirable toprovide means for retaining these parts in operative relationship inorder that the driving connection between the same may not beinterrupted due to excessive relative longitudinal movement thereof. Forthis purpose there-is provided a rod 88 which slidably extends throughstub shaft 84, threaded shaft 18 and a central opening in the member 34.The inner portion of rod 86 is of reduced diameter to provide a shoulderwhich normally abuts against the outer end of shaft 18. The inner end ofrod 88 is threaded to receive a nut 81 which abuts against the hub ofJaw member 34 and coacts with the shoulder on rod 88 to retain member 34and 18 in operative relationship.

As indicated in Figs. 2 and 3, the portable unit preferably includes amagnetically actuated switch 88 and aA manually operated switch 90, the

- latter being closeable by a push button 88, and

its contacts being in series with the winding of an electromagnet 9| andalso in series relationship to the source of current 92 by way of theconductor 83 which is one of the conductors passing through the cableindicated at 94 in Fig. 2. The first-named switch, when closed, allowspassage of current from the source 92 to the windings of the motor I8 asindicated by the connections in Fig. 3, and torque is thereby developedfor transmission to the engine crankshaft by way of the flexible shaft,gear train, and yieldable clutch heretofore described, the rotation ofsaid parts being effected to-produce automatic engagement between theclutch elements in the manner corresponding to that described in theprior art patents such as, for example, the Lansing Patent No. 1,962,397above referred to. Upon starting of the engine and the resultingautomatic disengagement of the clutch element. the operator uncouplesthe portable unit and transfers the same to the corresponding'xtureassociated with the o connecting cable 94, although the flow ofcurrentis, of course, interrupted at will by opening the switch 9U.

in the form of a coil spring which rests in an annular groove formed inthe outer periphery of said ring 83. The latter isadapted to rotate onthe curved lip surrounding the central opening in member 3|.

This application is a division of my copending application No. 351,831,filed August 8, 1940.

What is claimed is:

A portable aircraft accessory including an electric motor having anarmature shaft engaging a rotatable element carried by the aircraft, anenergizing circuit for said motor, said energizing circuit including anormally open'switch, means for closing said normally open switch, saidclosing means including a solenoid mounted on said portable' accessory,and means for holding said motor in driving engagement with saidrotatable element, said holding means comprising a handle having itsaxis disposed in a vertical line which intersects the longitudinal axisof said motor, and also the longitudinal axis of said solenoid, cuttingsalitio motor axis near the center of gravity of said mo r.

ROMEO M. NARDONE.

